A highly selective dual-signal response ratiometric fluorescence sensing strategy for malachite green in fish based on carbon dots/copper nanoclusters nanocomposite.

Malachite green (MG), a widely used antiparasitic agent, poses health risks to human due to its genotoxic and carcinogenic properties. Herein, a stable dual-emission fluoroprobe of carbon dots/copper nanoclusters is prepared for highly selective detection of MG based on the inner filter effect. This probe exhibits characteristic emission bands at 435 and 625 nm when excited at 376 nm. After adding MG, the both emission signals were significantly quenched, and the ratio of fluorescence intensity (F435/F625) was linearly related to the concentration of MG in the range of 0.05-40 µmol L-1 with a limit of detection of 18.2 nmol L-1. Meanwhile, the two signals exhibit linear relationships with the concentration of MG, respectively, and the corresponding detection results were consistent. The fluoroprobe was successfully used for the detection of MG in fish samples with the recoveries ranging from 96.0% to 103.8% and a relative standard deviation of <3.3%.

Fabrication of ß-cyclodextrin-polyacrylamide/covalent organic framework hydrogel at room temperature for the efficient removal of triazole fungicides from environmental water.

Triazole is frequently-used fungicide, which can leach into surface water through farmland and cause serious environmental pollution. Continuous exposure to triazole fungicides may cause harm to human health. Herein, ß-cyclodextrin-polyacrylamide/covalent organic framework (ß-CD-PAAM/TFPB-BD) hydrogel was fabricated at room temperature and used for the efficient removal of triazole fungicides. It displayed a short adsorption equilibrium time (50 min) and a total qe of 79.92 mg g-1. The adsorption process for triazole fungicides on ß-CD-PAAM/TFPB-BD hydrogel conforms to the pseudo-second-order kinetic model and Freundlich model. The prepared hydrogel was recyclable and resistant to salt, high temperature, acid, and alkali. The reusability of fabricated sorbent can be achieved (i.e., five extraction cycles) for removal of target fungicides. Moreover, the ß-CD-PAAM/TFPB-BD hydrogel was successfully applied to remove triazole fungicides in environmental water with removal efficiency ranging from 79.4% to 99.0%.